Resection of oral and maxillofacial tumors is often accompanied by the inferior alveolar nerve neurectomy, resulting in abnormal sensation in lower lip. It is generally believed that spontaneous sensory recovery in this nerve injury is difficult. However, during our follow-up, patients with inferior alveolar nerve sacrifice showed different degrees of lower lip sensory recovery. In this study, a prospective cohort study was conducted to demonstrate this phenomenon and analyze the factors influencing sensory recovery. A mental nerve transection model of Thy1-YFP mice and tissue clearing technique were used to explore possible mechanisms in this process. Gene silencing and overexpression experiments were then conducted to detect the changes in cell morphology and molecular markers. In our follow-up, 75% of patients with unilateral inferior alveolar nerve neurectomy had complete sensory recovery of the lower lip 12 months postoperatively. Patients with younger age, malignant tumors, and preservation of ipsilateral buccal and lingual nerves had a shorter recovery time. The buccal nerve collateral sprouting compensation was observed in the lower lip tissue of Thy1-YFP mice. ApoD was demonstrated to be involved in axon growth and peripheral nerve sensory recovery in the animal model. TGF-β inhibited the expression of STAT3 and the transcription of ApoD in Schwann cells through Zfp423. Overall, after sacrificing the inferior alveolar nerve, the collateral compensation of the ipsilateral buccal nerve could innervate the sensation. And this process was regulated by TGF-β-Zfp423-ApoD pathway.
Mice ; Animals ; Lip/innervation* ; Prospective Studies ; Mandibular Nerve/pathology* ; Sensation/physiology* ; Trigeminal Nerve Injuries/pathology*

Objective: To evaluate the risk factors of inferior alveolar nerve injury (IANI) after surgical removal of the mandibular third molars (M3) and present a new risk scoring system to predict the probability of IANI. Methods: Patients who underwent extraction of M3 in the Stomatology Hospital, Zhejiang University School of Medicine from April 2017 to December 2019 were involved. The investigators enrolled a sample composed of 949 mandibular third molars. Prediction model was used for univariate and multivariate analysis of gender, age, M3, inferior alveolar canal (IAC), and the contact between M3 and IAC, to assess the risk factors of IANI. Combined with the risk factors determined by the outcomes of prediction model, the risk scoring system was constructed. The diagnostic performance of each cut-off score was examined to conduct a risk stratification of IANI risk scores. The predictive ability and reliability of the model were evaluated. Results: In prediction model, twenty nine cases (4.4%, 29/664) experienced postoperative IANI. Number of root (P<0.01), depth of impaction (P<0.05), contact between M3 and IAC (P<0.01) and their contact position (P<0.05) were statistically significant as contributing risk factors of IANI. Specifically, the incidence of temporary IANI was higher in those who aged under 25 years (P<0.001), while female suffer more permanent injury (P<0.05). Based on the IANI risk scoring system, patients were stratified into low-risk, middle-risk and high-risk groups at cutoff scores of 3 and 4. The area under the receiver operator characteristic curve of the risk scoring system were 0.81 [95%CI (0.70-0.90), P=0.002] and 0.80 [95%CI (0.68-0.92), P=0.007] towards good discrimination. Conclusions: Age, gender, number of root, depth of impaction, and contact between M3 and IAC were risk factors of IANI. IANI risk scoring system might help in preoperative assessment, recognition of high-risk cases and decision-making to reduce IANI.
Aged ; Female ; Humans ; Mandible/surgery* ; Mandibular Nerve ; Molar, Third/surgery* ; Reproducibility of Results ; Risk Factors ; Tooth Extraction/adverse effects* ; Trigeminal Nerve Injuries/etiology*

OBJECTIVES: One of the most common complications of bilateral sagittal split ramus osteotomy (BSSRO) is neurosensory impairment of the inferior alveolar nerve (IAN). Accurate preoperative determination of the position of the IAN canal within the mandible using cone-beam computed tomography (CBCT) is recommended to prevent IAN dysfunction during BSSRO and facilitate neurosensory improvement after BSSRO.MATERIALS AND METHODS: This randomized clinical trial consisted of 86 surgical sites in 43 patients (30 females and 13 males), including 21 cases (42 sides) and 22 controls (44 sides). Panoramic and lateral cephalographs were obtained from all patients. In the experimental group, CBCT was also performed from both sides of the ramus and mandibular body. Neurosensory function of the IAN was subjectively assessed using a 5-point scale preoperatively and 7 days, 1 month, 3 months, 6 months, and 12 months post-surgery. Data were analyzed using Fisher's test, Spearman's test, t-test, linear mixed-model regression, and repeated-measures ANCOVA (α=0.05, 0.01).RESULTS: Mean sensory scores in the control group were 1.57, 2.61, 3.34, 3.73, and 4.20 over one year and were 1.69, 3.00, 3.60, 4.19, and 4.48 in the CBCT group. Significant effects were detected for CBCT intervention (P=0.002) and jaw side (P=0.003) but not for age (P=0.617) or displacement extent (P=0.122).CONCLUSION: Preoperative use of CBCT may help surgeons to practice more conservative surgery. Neurosensory deficits might heal faster on the right side.
Cone-Beam Computed Tomography ; Female ; Humans ; Jaw ; Mandible ; Mandibular Nerve ; Osteotomy, Sagittal Split Ramus ; Surgeons

BACKGROUND: The purpose of this study was to compare the pain perception and anesthetic efficacy of 2% lignocaine with 1:200,000 epinephrine, buffered lignocaine, and 4% articaine with 1:200,000 epinephrine for the inferior alveolar nerve block. METHODS: This was a double-blind crossover study involving 48 children aged 5–10 years, who received three inferior alveolar nerve block injections in three appointments scheduled one week apart from the next. Pain on injection was assessed using the Wong-Baker Faces pain scale and the sound eye motor scale (SEM). Efficacy of anesthesia was assessed by subjective (tingling or numbness of the lip, tongue, and corner of mouth) and objective signs (pain on probing). RESULTS: Pain perception on injection assessed with Wong-Baker scale was significantly different between buffered lignocaine and lignocaine (P < 0.001) and between buffered lignocaine and articaine (P = 0.041). The onset of anesthesia was lowest for buffered lignocaine, with a statistically significant difference between buffered lignocaine and lignocaine (P < 0.001). Moreover, the efficacy of local analgesia assessed using objective signs was significantly different between buffered lignocaine and lignocaine (P < 0.001) and between lignocaine and articaine. CONCLUSION: Buffered lignocaine was the least painful and the most efficacious anesthetic agent during the inferior alveolar nerve block injection in 5–10-year-old patients.
Analgesia ; Anesthesia ; Appointments and Schedules ; Buffers ; Carticaine ; Child ; Cross-Over Studies ; Epinephrine ; Humans ; Hypesthesia ; Lidocaine ; Lip ; Mandibular Nerve ; Pain Perception ; Tongue

OBJECTIVES: This study aimed to assess the effect of DentalVibe on the level of pain experienced during anesthetic injections using 2 different techniques. MATERIALS AND METHODS: This randomized crossover clinical trial evaluated 60 patients who required 2-session endodontic treatment. Labial infiltration (LI) anesthesia was administered in the anterior maxilla of 30 patients, while inferior alveolar nerve block (IANB) was performed in the remaining 30 patients. 1.8 mL of 2% lidocaine was injected at a rate of 1 mL/min using a 27-gauge needle. DentalVibe was randomly assigned to either the first or second injection session. A visual analog scale was used to determine participants' pain level during needle insertion and the anesthetic injection. The paired t-test was applied to assess the efficacy of DentalVibe for pain reduction. RESULTS: In LI anesthesia, the pain level was 12.0 ± 15.5 and 38.1 ± 21.0 during needle insertion and 19.1 ± 16.1 and 48.9 ± 24.6 during the anesthetic injection using DentalVibe and the conventional method, respectively. In IANB, the pain level was 14.1 ± 15.9 and 35.1 ± 20.8 during needle insertion and 17.3 ± 14.2 and 39.5 ± 20.8 during the anesthetic injection using DentalVibe and the conventional method, respectively. DentalVibe significantly decreased the level of pain experienced during needle insertion and the anesthetic injection in anterior LI and mandibular IANB anesthesia. CONCLUSIONS: The results suggest that DentalVibe can be used to reduce the level of pain experienced by adult patients during needle insertion and anesthetic injection.
Adult ; Anesthesia ; Anesthesia, Local ; Humans ; Lidocaine ; Mandibular Nerve ; Maxilla ; Methods ; Needles ; Visual Analog Scale

The lingual nerve (LN) is a branch of the mandibular division of the trigeminal nerve, and its injury is one of the major complications during oral surgery. This study aims to investigate the anatomy of the LN in the lower third molar area. Twenty sides from ten fresh-frozen adult cadaveric Caucasian heads were examined to measure the diameter of the LN. The mean diameter of the LN was 2.20±0.37 mm (range, 1.61–2.95 mm). There were no statistically significant differences in the measurements between sexes, sides, or tooth status (dentulous or edentulous). Understanding the anatomical features of the LN is essential for performing any surgical procedure in the oral region.
Adult ; Cadaver ; Head ; Humans ; Lingual Nerve ; Mandibular Nerve ; Molar, Third ; Surgery, Oral ; Tooth ; Trigeminal Nerve

PURPOSE: The aim of this study was to review the common conditions associated with mandibular canal widening. MATERIALS AND METHODS: General search engines and specialized databases including Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus were used to find relevant studies by using the following keywords: “mandibular canal,” “alveolar canal,” “inferior alveolar nerve canal,” “inferior dental canal,” “inferior mandibular canal,” “widening,” “enlargement,” “distension,” “expansion,” and “dilation.” RESULTS: In total, 130 articles were found, of which 80 were broadly relevant to the topic. We ultimately included 38 articles that were closely related to the topic of interest. When the data were compiled, the following 7 lesions were found to have a relationship with mandibular canal widening: non-Hodgkin lymphoma, osteosarcoma, schwannoma, neurofibroma, vascular malformation/hemangioma, multiple endocrine neoplasia syndromes, and perineural spreading or invasion. CONCLUSION: When clinicians encounter a lesion associated with mandibular canal widening, they should immediately consider these entities in the differential diagnosis. Doing so will help dentists make more accurate diagnoses and develop better treatment plans based on patients' radiographs.
Dentists ; Diagnosis ; Diagnosis, Differential ; Humans ; Lymphoma, Non-Hodgkin ; Mandibular Nerve ; Multiple Endocrine Neoplasia ; Neurilemmoma ; Neurofibroma ; Odontogenic Cysts ; Odontogenic Tumors ; Osteosarcoma ; Search Engine

PURPOSE: This study reviewed the common conditions associated with displacement of inferior alveolar nerve canal. MATERIALS AND METHODS: General search engines and specialized databases including Google Scholar, Pub Med, Pub Med Central, Science Direct, and Scopus were used to find relevant studies by using keywords such as “mandibular canal”, “alveolar canal”, “inferior alveolar nerve canal”, “inferior dental canal”, “inferior mandibular canal” and “displacement”. RESULTS: About 120 articles were found, of which approximately 70 were broadly relevant to the topic. We ultimately included 37 articles that were closely related to the topic of interest. When the data were compiled, the following 8 lesions were found to have a relationship with displacement of mandibular canal: radicular/residual cysts, dentigerous cyst, odontogenic keratocyst, aneurysmal bone cyst, ameloblastoma, central giant cell granuloma, fibrous dysplasis, and cementossifying fibroma. CONCLUSION: When clinicians encounter a lesion associated with displaced mandibular canal, they should first consider these entities in the differential diagnosis. This review would help dentists make more accurate diagnoses and develop better treatment plans according to patients' radiographs.
Ameloblastoma ; Aneurysm ; Bone Cysts ; Dentigerous Cyst ; Dentists ; Diagnosis ; Diagnosis, Differential ; Fibroma ; Granuloma, Giant Cell ; Humans ; Mandibular Nerve ; Odontogenic Cysts ; Odontogenic Tumors ; Search Engine

PURPOSE: The aim of this study was to evaluate the relationship between the mandibular canal and impacted mandibular third molars using cone-beam computed tomography (CBCT) and to compare the CBCT findings with signs on panoramic radiographs (PRs). MATERIALS AND METHODS: This retrospective study consisted of 200 mandibular third molars from 200 patients who showed a close relationship between the mandibular canal and impacted third molars on PRs and were referred for a CBCT examination of the position of the mandibular canal. The sample consisted of 124 females and 76 males, with ages ranging from 18 to 47 years (mean, 25.75±6.15 years). PRs were evaluated for interruption of the mandibular canal wall, darkening of the roots, diversion of the mandibular canal, and narrowing of the mandibular canal. Correlations between the PR and CBCT findings were statistically analyzed. RESULTS: In total, 146 cases (73%) showed an absence of canal cortication between the mandibular canal and impacted third molar on CBCT images. A statistically significant relationship was found between CBCT and PR findings (P<0.05). The absence of canal cortication on CBCT images was most frequently accompanied by the PR sign of diversion of the mandibular canal (96%) and least frequently by interruption of the mandibular canal wall (65%). CONCLUSION: CBCT examinations are highly recommended when diversion of the mandibular canal is observed on PR images to reduce the risk of mandibular nerve injury, and this sign appears to be more relevant than other PR signs.
Cone-Beam Computed Tomography ; Female ; Humans ; Male ; Mandibular Nerve ; Molar, Third ; Radiography, Panoramic ; Retrospective Studies ; Tooth, Impacted

In the case of edentulous patients, the total amount of occlusal force is dispersed by the keratinized gingiva during mastication, in result, causing lower masticatory and chewing efficiency. In particular, the mandibular area has more side effects such as pain than the maxilla has. It gets worse when the patient has more absorption of alveolar bone, but the implant treatment is often interrupted due to the existence of the inferior alveolar nerve. In this case, a patient treated with the all-on-4 method by placing the implant in the anterior part of mandible and with the conventional complete denture for the maxilla has maintained without complications and was satisfied with the restoration both functionally and esthetically.
Absorption ; Bite Force ; Denture, Complete ; Gingiva ; Humans ; Mandible ; Mandibular Nerve ; Mastication ; Maxilla ; Methods